Device for minimizing twisting of circular knit fabric



June 23, 1970 c. A. FOREMAN 3,516,268

DEVICE FOR MINIMIZING TWISTING OF CIRCULAR KNIT FABRIC Filed Sept. 12,19,68

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INVENTOR 27 27 CALEY A FOREMAN l I v ATTORNEYS United States Patent3,516,268 DEVICE FOR MINIMIZING TWISTING 0F CIRCULAR KNIT FABRIC CaleyA. Foreman, Grenada, Miss., assignor to US. In-

dustries, Inc., New York, N.Y., a corporation of Delaware Filed Sept.12, 1968, Ser. No. 759,299 Int. Cl. D04b /88 U.S. Cl. 66-149 6 ClaimsABSTRACT OF THE DISCLOSURE A device for minimizing the twisting offabric produced on circular knitting machines, which device isparticularly useful when the fabric is of considerable length as forexample waist length stockings or panty hose, especially those ofstretch yarn which are loosely knitted in order to permit laterdevelopment of crimp or stretch characteristics.

In a circular knitting machine the fabric is taken off within the needlecylinder by means of a take-off device which may be of any one of anumber of types, but which is intended to permit rotation of the fabricwith the needle cylinder at all times.

Recently ladies stockings have been knitted in much greater lengths thanheretofore due to the fact that panty hose comprising two stockings ofwaist length has become popular and due also to the fact that yarns havebeen developed which require loose knitting and subsequent crimpdevelopment, resulting in the knitted fabric being much longer thanpresent takeup devices can care for, and likewise resulting in twistingof the fabric, particularly when the take-up carriage drops to its lowerlimit and is no longer held up by the fabric, or in the case of a vacuumtake-up, when the fabric accumulates in the vacuum tube. In addition,there is likely to be some twisting resulting through air or fabric tubefriction and even on machines not equipped with take-up facilities, thefabric has a tendency'to twist due to air or fabric tube friction or toreaching the floor beneath a machine.

Although attempts have been made to solve the problem of twisting byelevating the machine to provide more floor-to-knitting head length, orby installing greaterdiameter fabric tubes to permit the fabric toballoon out to foreshorten the fabric, these attempts have met with verylimited success, since the fabric tube or air friction, or both, stilltends to cause the fabric to lag behind the cylinder rotation.

There are a number of disadvantages of this twisting, amongst Which isthe fact that when knitting yarns which are subsequentlycrimped-developed, the fabric must be straightened before it can besteamed to develop the crimp, since if it is not, the crimp will beunevenly de veloped and shaded areas will result. This prevents theblowing of the stockings into a bag for subsequent steam setting andrequires that the twisted fabric be untwisted and laid out flat, whichis time-consuming and hence expensive. Additionally, when low-denierfabric in the range of from 15 to 45 denier is twisted, the loops tendto lock together and cause pulled threads when the fabric is untwisted.Furthermore, tension of the pull-off is uneven, resulting indifferential stitches and stitch distortion.

My invention is simple and inexpensive while at the same time providinga positive means for substantially preventing fabric twist. My inventionconsists essentially of a tube or rod extending downwardly centrally ofthe needle cylinder and driven synchronously with that cylinder toprovide a rotating core about which the fabric 3,516,268 Patented June23, 1970 accumulates as it is knit. The fabric adheres to this core andtherefore continues at all times to rotate with the needle cylinder sothat no twisting of the fabric occurs. Any tendency of the fabric totwist, as a matter of fact, merely causes it to adhere to the core andto thus even more positively rotate with the core and prevent other thana very slight initial twisting.

It is a primary object of the invention, therefore, to provide a devicefor use with a circular knitting machine which prevents or minimizes thetwisting of fabric and thus minimizes the defects resulting from theknitting of long fabric lengths, while at the same time requiring noextensive changes in the knitting machine and thus being relativelyinexpensive to manufacture and install.

Other objects and features of the invention will become apparent whenthe following description is considered in connection with the annexeddrawings, in which:

FIG. 1 is a schematic fragmentary vertical crosssectional view of aconventional circular knitting machine, modified in accordance with myinvention. The machine so modified is of the type normally having amechanical take-off, and

FIG. 2 is a view similar to FIG. 1, but showing my invention applied toa circulating knitting machine having a vacuum take-off.

Referring now to the drawings and particularly to FIG. 1, there is showntherein a conventional circular knitting machine generally designated10, having a needle cylinder 11 carrying the needles 12 and carryinglikewise the usual sinker ring 13 and sinkers 14. In addition, as iscustomary, the machine includes a transfer dial jack 15 carryingtransfer jacks (not shown) and the needle cylinder 11 and transfer dial15 are driven in synchronism through the medium of gearing including thebevel gear 16 and the bevel gear 18.

In the usual manner, a fabric tube 20 is fixed by any suitable meanswithin the needle cylinder 11 and fixed supporting cylinder 21. Thefabric, as it is produced by the needles 14, falls into this tube 20. Inthe type of machine having a mechanical take-off arrangement, it iscustomary to supply a cup 22, which in a manner not shown in FIG. 1, canbe elevated to an upper position and operated in such a manner as tograb the end of the fabric after a short length has been produced andlowered at the rate of fabric production until it reaches a lowerposition, where it remains until the knitting is completed, after whichit is moved to a still lower position and the fabric blown out, by meansof an air jet 30 into a receptacle cup 32. The cup 22 is mounted in anysuitable manner to cause these motions and is freely rotatable on avertical axis so that the fabric can cause rotation of the cup. As hasbeen stated above, when the stocking is of great length, the mechanicaltake-up device does not function well, in part because the cup 22 whenin its intermediate position is not driven by the fabric and the fabricballoons out and engages the tube 20 or the cylinder 21, or as a resultof air friction, becomes twisted.

By my invention I support a rod or tube 23 from the dial 15, thusproviding a rotating core about which the fabric is deposited as it isknit. Preferably the rod 23 is fixed to the dial 15 by means of a spring24 so that the dial may be tilted to provide for normal maintenance,although other types of flexible connection may be utilized, and the rodmay be driven in other manner synchronously with the needle cylinder.

The customary grab type take-up is modified so that it consists of adisc or platform 25 mounted on the cup 22, with no provision forelevating the cup to an upper limit and with no provision for grabbingthe fabric while the cup is in that upper position. On the contrary, the

cup 22 terminates in the disc 25 which is fixed thereto, the cup 22rotating as usual on antifriction bearings while supported on the pistonrod of a pneumatic cylinder 27. It will be understood of course that inplace of the pneumatic cylinder 27 a mechanically operated device whichis in common use may be substituted and operated by cams driven by thedrive mechanism of the knitting machine in a customary manner.

The disc 25 is provided centrally thereof with a depression 28 and iscupped as indicated. The lower end of the core rod or tube 23 is conicalor rounded and mates with the depression 28 so that the core drives thecup 22 and disc 25. It should be noted at this time that the core rod ortube 23 is highly polished throughout, as is the surface of disc 25, inorder to prevent snags in the fabric.

As has been indicated, the usual pulley and weight mechanism for causingthe grab mechanism to be elevated to a position just under the innertube 20 is omitted when my improved take-off device is utilized, sinceit no longer would serve any function, due to the extreme length of thestockings intended to be knitted, as mentioned above. As is usual in anarrangement of this sort, when the stocking has been finished andpressed off, the control mechanism of the knitting machine admits airunder pressure to the cylinder 27 and simultaneously to a jet 30. Thejet 30 is situated diametrically across the outer tube 21 from adischarge tube 31. Thus, when the disc 25 is lowered, the jet causes thestocking to pass into the tube 31 and to be driven upwardly and bedeposited in the receptacle 32, from which it may be manually taken or,in some instances, discharged through a pneumatic system to a centralpoint.

Referring now to FIG. 2, it should be noted that the same referencecharacters have been utilized in designating similar parts in theapplication of my invention to the common vacuum type take-offmechanism. As shown in FIG. 2, the tube or rod 23 is made in two parts,one of a lesser diameter than the other, as illustrated at 23a and 23b,in order to accommodate the device to the inner tube 20 which normallyhas a lesser diameter than the corresponding fabric tube of a machinehaving mechanical grab type take-off. The device is otherwise the sameand operates in the same manner to assure that there will be no rotationof any portion of the knitted fabric tube relative to the needlecylinder and transfer jack dial.

In this instance the take-off mechanism comprises a lower innerperforated cylinder 40 together with an outer supporting cylinder 41,the inner cylinder having an opening 42 which permits egress of thetubular fabric when the piston rod 26 is lowered. Joined to the outercylinder 41 is a tube 43, which at its upper end extends into a housing44 and is perforated, as indicated at 45, within that housing.

During knitting, vacuum is applied to a tube 46 and therefore to thehousing 44, perforations 45, tube 43, and through perforations of theinner tube 40 to that inner tube and thus causes the stocking to bedrawn downwardly through the fabric tube 20 and to accumulate upon thedisc 25. Tube 43 is closed at its upper end by a pivoted top 47, and thehousing 44 has an extended portion 48 which terminates in a tube 49having a U-bend enabling it to discharge into a receiving basket 50.Also, at the lower bend of the tube 43 there is provided an air jet 51which is similar to the air jet 30 described in connection with the FIG.1 application. When a stocking has been completed the control mechanismof the knit ting machine causes the cylinder 27 to actuate and pull downthe piston rod 26, thus freeing the lower end of the fabric, and at thesame time a jet of air is emitted through the jet 51, which causes thestocking to be expelled into tube 48 through the top 47, tube 46 thenbeing closed by a valve 52 also operated by the knitting machine controlmechanism and the pivoted cover 47 being open. As a result, the stockingis propelled through the tube 49 and is received in the basket 50.

As mentioned hereinabove in connection with the application of myinvention to the mechanical grab type take-off, a pneumatic conveyorsystem may be connected to the individual receiving baskets 50 so thatstockings may accumulate and be taken from the machines of a group undera specialized control. However, this forms no part of the presentinvention, which is limited entirely to the provision of means forassuring that stockings will not be so twisted during the knitting andtake-off thereof as to prevent proper crimp development and otherdetrimental effects.

Also as has been indicated the preferred mode of operation is to drivethe rod 23 from the needle dial and by friction drive the disc orplatform from the rod. However, it is entirely possible to mount the rod23 on the needle dial for freer rotation with respect thereto and todrive the disc 25 either through connection to the piston rod 26 orotherwise synchronously with the needle cylinder.

1 While I have described a preferred form of my invention and have shownit as applied to slightly different forms of circular knitting machinesin common use, it is to be understood that many variations would bepossible and I therefore wish to be limited not by the foregoingdescription, but on the contrary, solely by the claims granted to me.

- What is claimed is:

' 1. A device for preventing twisting of fabric as it is knitted by acircular knitting machine having a rotating needle cylinder and asynchronously rotating concentric dial and in which the fabricaccumulates within the said disc for limited vertical movement relativeto said dial and rod, means normally urging said disc upwardly againstsaid rod and means for driving said rod and disc synchronously with theneedle cylinder.

2. A device as claimed in claim '1 wherein said rod is fixed to saiddial and wherein said disc is mounted for free rotation about a verticalaxis in alignment with the axis of said dial.

3. A device as claimed in claim 1 wherein means are provided to movesaid disc downwardly away from said rod upon completion of apredetermined fabric length.

45A device as claimed in claim 1 wherein said rod hasa curved lower endand said disc has a mating depression centrally of the upper surface.

5. A device as claimed in claim 1 wherein said rod and said disc arehighly polished.

- 6. A device as claimed in claim 1 wherein said rod is connected to thedial by means of afiexible connection whereby said dial may be tipped topermit inspection.

References Cited UNITED STATES PATENTS 3,071,948 1/1963 Comas 66-1493,214,944 11/1965 Kienez 66-149 RONALD FELDBAUM, Primary Examiner

